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中文 / EN
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The are a number of protocols for consumer infrared, likes RC5, SIRCS, Sy, RECS80, Denon, NEC, Motorola, Japanese, SAMSWNG and Daewoo. We only support NEC protocol in our Rockchip platform which is most widely used in Mainland China market.
How does it work
The PWM module of Rockchip can be configured into three modes for measuring input waveform, reference, one shot and continueous mode. We use the reference mode for the IR remote controller. After the PWM module measure the last time of the input waveform, it would issue an interrupt to the CPU.
For the IR remote controller, it would send a sequence signals to the IR receiver which is connected to a PWM module in our board. We can parse signals based on the interrupt of PWM. Here is a sample of NEC protocol.
A sample configure of the device tree
&pwm3 {
status = "okay";
pinctrl-names = "default";
interrupts = <GIC_SPI 61 IRQ_TYPE_LEVEL_HIGH 0>;
compatible = "rockchip,remotectl-pwm";
remote_pwm_id = <3>;
handle_cpu_id = <1>;
ir_key1 {
rockchip,usercode = <0x4040>;
rockchip,key_table =
<0xf2 KEY_REPLY>,
<0xba KEY_BACK>,
<0xf4 KEY_UP>,
<0xf1 KEY_DOWN>,
<0xef KEY_LEFT>,
<0xee KEY_RIGHT>,
<0xbd KEY_HOME>,
<0xea KEY_VOLUMEUP>,
<0xe3 KEY_VOLUMEDOWN>,
<0xe2 KEY_SEARCH>,
<0xb2 KEY_POWER>,
<0xbc KEY_MUTE>,
<0xec KEY_MENU>,
<0xbf 0x190>,
<0xe0 0x191>,
<0xe1 0x192>,
<0xe9 183>,
<0xe6 248>,
<0xe8 185>,
<0xe7 186>,
<0xf0 388>,
<0xbe 0x175>;
};
ir_key2 {
rockchip,usercode = <0xff00>;
rockchip,key_table =
<0xf9 KEY_HOME>,
<0xbf KEY_BACK>,
<0xfb KEY_MENU>,
<0xaa KEY_REPLY>,
<0xb9 KEY_UP>,
<0xe9 KEY_DOWN>,
<0xb8 KEY_LEFT>,
<0xea KEY_RIGHT>,
<0xeb KEY_VOLUMEDOWN>,
<0xef KEY_VOLUMEUP>,
<0xf7 KEY_MUTE>,
<0xe7 KEY_POWER>,
<0xfc KEY_POWER>,
<0xa9 KEY_VOLUMEDOWN>,
<0xa8 KEY_VOLUMEDOWN>,
<0xe0 KEY_VOLUMEDOWN>,
<0xa5 KEY_VOLUMEDOWN>,
<0xab 183>,
<0xb7 388>,
<0xe8 388>,
<0xf8 184>,
<0xaf 185>,
<0xed KEY_VOLUMEDOWN>,
<0xee 186>,
<0xb3 KEY_VOLUMEDOWN>,
<0xf1 KEY_VOLUMEDOWN>,
<0xf2 KEY_VOLUMEDOWN>,
<0xf3 KEY_SEARCH>,
<0xb4 KEY_VOLUMEDOWN>,
<0xbe KEY_SEARCH>;
};
ir_key3 {
rockchip,usercode = <0x1dcc>;
rockchip,key_table =
<0xee KEY_REPLY>,
<0xf0 KEY_BACK>,
<0xf8 KEY_UP>,
<0xbb KEY_DOWN>,
<0xef KEY_LEFT>,
<0xed KEY_RIGHT>,
<0xfc KEY_HOME>,
<0xf1 KEY_VOLUMEUP>,
<0xfd KEY_VOLUMEDOWN>,
<0xb7 KEY_SEARCH>,
<0xff KEY_POWER>,
<0xf3 KEY_MUTE>,
<0xbf KEY_MENU>,
<0xf9 0x191>,
<0xf5 0x192>,
<0xb3 388>,
<0xbe KEY_1>,
<0xba KEY_2>,
<0xb2 KEY_3>,
<0xbd KEY_4>,
<0xf9 KEY_5>,
<0xb1 KEY_6>,
<0xfc KEY_7>,
<0xf8 KEY_8>,
<0xb0 KEY_9>,
<0xb6 KEY_0>,
<0xb5 KEY_BACKSPACE>;
};
};
You can find standard key value table at include/dt-bindings/input/input.h of Linux kernel.
The path of the drive file
/kernel/drivers/input/remotectl/rockchip_pwm_remotectl.c
How to add support for a new remote controller and debug
1. How to get a IR key of a button
Enable the debug info at kernel
echo 1 > /sys/module/rockchip_pwm_remotectl/parameters/code_print
Then press a button at your remote controller, when the receiver received that signal, you can see a message from kernel log
[19634.735833] GET USERCODE=0x4040
[19634.762463] RMC_GETDATA=e9
We should know the usercode of that remote controller is 0x4040 and the button you just press is 0xe9.
Following the procedure above, you can configure all the buttons in a controller.
2. When the kernel can't report an available value
You may need to read the driver, adjust the condition of the key value detection from PWM input.
3、Nothing is wrong at kernel but your application still won't work
Maybe it is not the fault of the kernel, we have a way to check whether userspace can receive the input event from the kernel. Using getevent command, we would know all the input events from kernel.
If you got the correct key value from kernel without missing, I could sure you should blame the Android.
shell@rk3399:/ # getevent
add device 1: /dev/input/event0
name: "ff680000.pwm"
/dev/input/event0: 0001 006c 00000001
/dev/input/event0: 0000 0000 00000000
/dev/input/event0: 0001 006c 00000000
/dev/input/event0: 0000 0000 00000000
The above message shows that we receive a key event while its key value is 0x6c here. 00000001 for pressed and 00000000 for its released.